The DHCP Relay implementation in Cisco Adaptive Security Appliance (ASA) Software 8.4.7.29 and 9.1.7.4 allows remote attackers to cause a denial of service (interface wedge) via a crafted rate of DHCP packet transmission, aka Bug ID CSCuy66942.
http://www.securitytracker.com/id/1036961
http://www.securityfocus.com/bid/93408
http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20161005-asa-dhcp